1. Field of the Invention
The present invention relates to backflow prevention assembly and, more specifically, to a backflow prevention assembly which includes a detection system for detecting backflow conditions.
2. Background Information
Backflow prevention assemblies have long been used to prevent a fluid source, such as a source of drinking water, from being contaminated with potentially unsafe liquids within a distribution system to which the fluid source is connected. A typical situation includes connection of drinking water supply to process systems of industrial buildings, steam boilers, pressure steam cookers, irrigation systems and fire suppression systems. Government regulations typically require the use of a backflow preventer when such cross connections are present.
Most modern building codes require that backflow preventers include a pair of independently spring-loaded positive check valves connected in tandem within the backflow preventer. The pair of check valves are provided so that each can serve as a backup in case the other should fail. In the event that both check valves should become fouled or otherwise fail, a discharge and a relief valve are often positioned between the first and second check valves. In this manner, if both check valves should fail during backflow conditions, the system will be emptied by the actuation of the relief valve opening the discharge. Examples of such check valves and relief valve systems can be found in U.S. Pat. No. 4,991,655 to McHugh. Further examples are Wilkins Backflow Preventer Models 975 and 975DA sold by Wilkins Regulator Division of Zurn Industries, Inc. The disadvantage of these prior art systems is that there is no indication as to when the relief valve is open and backflow condition is occurring. This presents a large problem in areas where the discharge is positioned in locations susceptible to flood damage, such as hidden areas or areas protected from freezing, or in areas where there is a high premium for water.
It is an object of the present invention to overcome the problems of these prior art systems. It is a further object of the present invention to provide a backflow prevention and detection system which provides a simple, effective and efficient mechanism for preventing backflow and indicating when backflow conditions are present.